The external parts of watches and similar apparatus are subject to numerous constraints, in particular of impermeability, robustness, appearance, and must be produced so as to prevent any involuntary dismantling which inevitably results in an after-sales intervention for changing seals, cleaning, lubrication or even repair.
Some components of external parts or for control must, once again, be angularly indexed, one relative to the other, for relocation to the original reference position, inactive or active, or even to facilitate reading of signs or graduations, or for ensuring the continuity of out-of-true and/or decorative surfaces. This angular indexing is often difficult to achieve well, in combination with good locking of the components and with perfect sealing of the joints.
Document EP2476335A1, in the name of De Retz, describes a piece of jewellery with two lateral annular bodies, the diameters of which are greater than a diameter of a central annular body. One of the lateral bodies is assembled with the central body in a removable manner in order to position and remove the annular decorative elements. A magnetic locking unit, i.e. a tooth, retains the lateral bodies on the central body in an assembled position defined by another locking unit between the lateral and central bodies, along a degree of freedom. This latter locking unit is formed by a projecting unit, i.e. a fillet, by a projecting part and a groove provided with an open part and a closed part.
Document EP2537431A1, in the name of Aravelo Martin, describes a device for connecting precious elements to a finger ring, comprising a substantially annular body to be worn on a finger, and a gem support connected to the annular body in an upper region. The substantially annular body comprises, at one point of the latter, a head which is integral with the latter and is inserted and coupled to a lower part of the gem support by means of a bayonet coupling.